In order to check the performance of a balance, generally, repetition performance thereof is measured by placing a balance weight from the outside and removing it from a weighing pan. In this case, an external balance weight is necessary, and further, if an operator does not have the skill of placing and removing the balance weight, performance of the balance cannot be correctly measured. In particular, in the case of an analytical balance with high sensitivity, precautions for measurement must be observed such as paying attention to the movement of the surrounding air when placing a weight, opening and closing a windshield in a short time, and not inserting a hand into the windshield to prevent the generation of a convection flow. If the surrounding environment or the measuring manner is improper, when the results of repetition performance measurement are poor, it cannot be known whether the poor results were caused by an improper surrounding environment or measuring manner or whether a failure to bring about performance of the balance was truly not realized, and finally it becomes impossible to accomplish the purpose of performing accurate weighing.
Among recent balances, there are known balances that have a built-in balance weight in an internal mechanism of the balance, and solves the above-described problem by automatically placing and removing the built-in balance weight, and accordingly enables performance confirmation (for example, Patent Literature 1 and Patent Literature 2).